Conventionally, some ejectors are known to be applied to a vapor compression refrigeration cycle device and to serve as a decompressor. This kind of ejector includes a nozzle portion for decompressing a refrigerant, and is designed to draw a gas-phase refrigerant flowing out of an evaporator by a suction effect of an injection refrigerant injected from the nozzle portion, and to pressurize a mixed refrigerant including the injection refrigerant and the drawn refrigerant by a pressure-increasing portion (diffuser).
Thus, the refrigerant cycle device including the ejector as the decompressor (hereinafter referred to as an “ejector refrigeration cycle”) raises the pressure of the refrigerant drawn into a compressor by a refrigerant pressurizing effect by the pressure-increasing portion of the ejector, and thus can reduce the power consumption of the compressor. Thus, the ejector refrigeration cycle can improve a cycle coefficient of performance (COP) as compared to a normal refrigeration cycle device including an expansion valve or the like as the decompressor.
Further, Patent Document 1 discloses an ejector refrigeration cycle that is applied to an air conditioner to adjust the temperature of air blown into a space to be air-conditioned. The ejector refrigeration cycle disclosed in Patent Document 1 includes a refrigerant circuit switch for switching a refrigerant circuit for circulation of the refrigerant, and can perform switching among various refrigeration circuits according to an operation mode.
For example, in an air cooling mode of cooling the space to be air-conditioned by cooling air as a fluid to be heat-exchanged, switching is performed to a refrigerant circuit for dissipating heat absorbed by the refrigerant from air in an interior evaporator, into an outside air in an exterior heat exchanger. In an air heating mode of heating the space to be air-conditioned by heating air, switching is performed to a refrigerant circuit for dissipating the heat absorbed by the refrigerant from the outside air in an exterior heat exchanger, into the air in an interior condenser.